COMSOL 4.2a Release Highlights

Released October 14, 2011

COMSOL has built a solid reputation of fast-paced innovation for multiphysics simulation and analysis.
The new Version 4.2a adds to the long history of successful releases of the flagship COMSOL Multiphysics
product suite. By including features that reach new communities of engineers and scientists, COMSOL is
creating a tightly-integrated platform for analysis whose breadth and depth is unmatched. Major news in
the Version 4.2a release:

Magnetic
prospecting
is a method for
geological exploration
of iron ore deposits. The
picture shows a simulation where imported terrain data was used to
represent the underlying geometry. Passive magnetic prospecting
relies on accurate mapping of local geomagnetic anomalies. This model
estimates the magnetic anomaly for both surface and aerial
prospecting by solving for the induced magnetization in the iron ore
due to the earth's magnetic field.

Particle Tracing Module

The Particle Tracing Module extends the functionality of the COMSOL Multiphysics
environment for computing the trajectory of particles in a fluid or electromagnetic field,
including particle-field interactions. Any add-on module combines seamlessly with the
Particle Tracing Module and gives you access to additional modeling tools and fields
to drive the particle motion.

This flow simulation
computes the trajectories of quartz
particles through a static mixing device. Due to the
fact that the particles
have mass, only a certain fraction make it to the outlet. This
fraction, the transmission probability, is computed during
postprocessing.

A mass spectrometer is used to separate and identify different substances from a sample.
Applications are numerous including materials engineering and environmental science. The
picture shows a particle tracing simulation with trajectories of ions of various molecular
weights in a quadrupole mass spectrometer. The electric fields has both AC and DC components
and the combination of the two is essential for the function of the spectrometer.

LiveLink™ for Creo™ Parametric

With the new LiveLink for Creo Parametric, COMSOL Multiphysics can be seamlessly integrated
with the latest design software from PTC®. By establishing an associative connection between
the two applications, a change of a feature in the CAD model automatically updates the geometry in
COMSOL Multiphysics, while retaining physics settings. All parameters specified in Creo Parametric
can be interactively linked with your simulation geometry. This enables multiphysics simulation
involving parametric sweeps and design optimization in sync with the CAD program. The LiveLink for
Creo Parametric includes all the capabilities of the CAD Import Module and enables import and
defeaturing of CAD files from all major CAD packages.

Model Library, Animations, and Images

COMSOL Multiphysics’ extensive Model Library is now accessible from within the One Window Interface
that is included with the LiveLink for SolidWorks. Animations and images can now be created from the
One Window Interface and a series of performance enhancements make for quicker synchronization of large
models.

The LiveLink for SolidWorks now makes available animations and image generation from its One Window Interface.

LiveLink for MATLAB

LiveLink for MATLAB

The new version of the LiveLink for MATLAB includes numerous optimizations for
improved performance and memory handling as well as new and updated functions,
including a user interface for navigating COMSOL’s Model Library.

The new tutorials for the LiveLink for MATLAB help you get up to speed with combining
MATLAB with COMSOL. Detailed step-by-step instructions are available on HTML and PDF formats

New Tutorials

Five new Model Library tutorials demonstrate how to efficiently
combine MATLAB scripting with COMSOL Multiphysics simulations. These
models show capabilities that are unique to the LiveLink for MATLAB
such as extracting data at the MATLAB prompt, running models in
nested MATLAB for-loops, using previous solution data within MATLAB,
and calling external MATLAB functions from the COMSOL Desktop:

Domain Activation and Deactivation
This model of a time-dependent heat-transfer problem implements heating from alternating
regions by using domain activation and deactivation.

Homogenization in a Chemical Reactor
This model illustrates how to simulate a periodic homogenization process in a space-dependent
chemical reactor model. This homogenization removes concentration gradients in the reactor at
a set time interval.

Convective Heat Transfer with Pseudo-Periodicity
This model simulates convective heat transfer in a channel filled with water. To reduce memory
requirements, the model is solved repeatedly on a pseudo-periodic section of the channel. Each
solution corresponds to a different section, and before each solution step the temperature at
the outlet boundary from the previous solution is mapped to the inlet boundary.

Temperature Distribution in a Thermos
This example solves for the temperature distribution inside a thermos holding hot coffee. The
main purpose is to illustrate how to use MATLAB functions to define material properties and
boundary conditions.

Geometry Parametrization using the LiveLink for Solidworks
This example shows geometry parametrization using both the LiveLink for Solidworks and the LiveLink
for MATLAB. MATLAB is used to created nested loops that change geometry parameters and update the
geometry using the LiveLink for Solidworks. The same modeling approach also works with the LiveLink
for AutoCAD, LiveLink for Creo Parametric, LiveLink for Pro/ENGINEER, LiveLink for Inventor, and
the LiveLink foir SpaceClaim.

LiveLink for SpaceClaim

LiveLink™ for SpaceClaim™

The LiveLink for SpaceClaim brings you the fusion of direct modeling and
multiphysics simulation in a tightly integrated environment, enabling optimal
designs and collaboration across CAD and CAE teams.

The LiveLink for SpaceClaim interface allows you to transfer a 3D geometry
from SpaceClaim to COMSOL Multiphysics. The synchronized geometry in the COMSOL
model stays associative with the geometry in SpaceClaim. This means that settings
applied to the geometry, like physics or mesh settings, are retained after subsequent
synchronizations. The LiveLink interface is also bidirectional to allow you to initiate
a change of the SpaceClaim geometry from the COMSOL model.

The latest version has increased performance for synchronizing larger CAD models.

The latest version of the LiveLink for SpaceClaim comes with increased performance for synchronizing larger CAD models.

CAD Import Module

CAD Import Module

The Parasolid® geometry kernel from Siemens PLM is now the default
geometry kernel for users of any of the following products: CAD Import Module,
LiveLink for AutoCAD, LiveLink for Inventor, LiveLink for Pro/ENGINEER,
LiveLink for Creo Parametric, LiveLink for SolidWorks, LiveLink for SpaceClaim.

The Parasolid kernel enables more advanced geometry operations and allows for
creation and handling of complex CAD models within the native COMSOL Multiphysics
geometry modeling environment. Without any add-on products, users can still create
geometry models in the native COMSOL Multiphysics environment but with the functionality
of COMSOL’s native geometry kernel.

Automatic scaling is now enabled for handling CAD models of vastly different length
scales ranging from nanodevices to mountains and beyond.

This structural simulation tutorial uses the
submodeling technique to accurately resolve
the stress concentrations in a wheel rim. First
a global model is solved to obtain the
displacements, which are then used as boundary
conditions in a local model of the region where the stress concentrations
occur. The CAD Import Module and certain LiveLink products enable import
and geometry repair of the original CAD model. With these products added,
the geometry representation now defaults to the Parasolid kernel from Siemens
PLM, which is also used when creating geometries from scratch. This enables
handling of more advanced geometry objects.

Mesh and Geometry

Interpolation Curves

Interpolation curves can be created from tabulated x,y or x,y,z data in both
2D and 3D. A cubic spline interpolates or approximates the given points – controlled
by a user-defined tolerance. Data can be loaded from file or directly typed in the
Interpolation Curve settings window. Curves can be open, closed, or automatically
turned into a solid object. Such objects can be used for 2D analysis or be extruded,
revolved, and combined to form 3D objects. Interpolation curves in 3D can be used as
the spine of a geometric sweep or to guide and control mesh density as well as for
postprocessing purposes.

The screenshot shows an electrical resistance calculation for a copper wire created with a
geometric sweep along an interpolation curve with x,y,z data imported from file.

Cut-and-Paste Geometry Objects

You can now cut-and-paste or duplicate one or multiple geometry objects and operations
in the Model Builder tree’s Geometry node. This avoids reproducing complicated geometry
objects or sequences of geometry operations and allows for faster geometry creation and parameterization.

Extended Swept Meshing

Swept meshing can now be used between partitioned surfaces. A surface partitioned in N
segments can be swept into a surface of M segments, where N ≥ M. In general, it is required
that the partitioning of the source (into faces) is a refinement of the partitioning of the
destination.

The virtual geometry functionality has been generalized to cover swept meshes for geometry
objects with surfaces where virtual geometry operations have been made.

A swept mesh
going from a surface partitioned in 5 segments to a surface of 2
segments. This new feature allows for mesh sweeps between
differently partitioned surfaces and makes hexahedral and prismatic
meshes available for a larger class of thin objects.

Interpolation curves are available in both 2D and 3D. Curves can be open, closed,
or automatically be turned into a solid object. Such objects can be used for 2D
analysis or be extruded, revolved, and combined to form 3D objects.

Reuse Parameterized Geometry Objects

You can now reuse parameterized geometry objects between simulations by inserting
a geometry sequence from another model file. The geometry sequence in the Model Builder
tree defines the geometric objects and the sequence of operations used to combine them
into composite shapes. If the geometry sequence contains references to functions or
parameters, those functions and parameters are also inserted into the model.

Extended Mesh Copying

New copy mesh functionality makes it possible to copy a mesh from a partitioned surface
to a similar surface using an automatic rigid-body transformation. This functionality is
important for periodic boundary condition applications with high-accuracy requirements
such as cyclic symmetry for structural analysis and Floquet boundary conditions for
electromagnetic wave propagation. The new features are available as Copy Domain, Copy
Face, and Copy Edge.

A triangular surface mesh is copied to its opposing side. Meshes that are copied
using rigid body translations are important for periodic boundary condition
applications with high-accuracy requirements such as cyclic symmetry for structural
analysis and Floquet boundary conditions for electromagnetic wave propagation.

Sketch on Work Planes in 3D

It is now possible to interactively sketch 2D primitives on work planes directly in
3D allowing for easier geometry object positioning. Activate by selecting the checkbox
Draw on work plane in 3D. The feature requires a graphics card with support for texture
rendering. The default is still 2D work plane sketching but you can permanently switch
the new work plane behavior on by changing a preference entry. Two new toolbar buttons
provide Work Plane Clipping and Align with Work Plane functionality for simplifying
geometry creation using work planes.

Image Import

You can now use image data to represent 2D material distributions or to identify regions with
different materials by their color or gray scale. Images used in this way can have many origins
such as scanning electron microscope (SEM), computed tomography (CT), or magnetic resonance imaging (MRI).

An important application of image import is for easy computation of equivalent volume-averaged
material properties for highly inhomogeneous or porous materials. This includes properties such as
conductivity, permittivity, elasticity, or porosity and allows for converting spatially distributed
values to a single representative averaged value. Such equivalent material properties can then be
used for simulations of larger structures avoiding detailed microscopic information. This modeling
approach has several advantages such as avoiding the often difficult operations of image segmenting
and image-to-geometry conversion. It also brings greatly simplified meshing, less memory usage, and
shorter computation times--this can be particularly important when the same type of analysis needs
to be repeated many times for different images.

An imported image is made available as a general COMSOL interpolation function that can be used
for any modeling purposes.

A tetrahedral volumetric mesh created on a geometry that combines rectangular
solids with imported DEM data of the topography of Mount McKinley. Such geometry
representations can be used for any type of simulations in COMSOL Multiphysics.

The pictures shows a simulation where the pore structure is represented implicitly
by a gray-scale picture instead of explicitly by a CAD geometry. A flow simulation
of the structure is run against a mesh generated on a single rectangle. Such meshes
can be generated very quickly and without human intervention. An adaptive mesh was
used to increase accuracy. The level of detail of the simulation result can be
controlled very easily by coarsening or refining the mesh and be set to meet
specified solution time goals where accuracy is traded against speed.

Digital Elevation Map (DEM) Import

Topographic data from geographic information system (GIS) applications can now be imported
with a new Digital Elevation Map interpolation function feature with direct support for the
DEM file format from U.S. Geological Survey (USGS). You can freely combine DEM surfaces with
other surfaces and solids to form a volumetric representation of both geometry and mesh.
Multiple DEM surfaces can be combined and intersected as well as embedded inside of other
geometrical objects in order to form composite structures. This function utilizes the
parametric surface geometry primitive to enable resolution control by varying the number
of “knots” of an underlying approximation surface. This way you can start with a rough
approximation of the DEM data for quicker computations and when you are satisfied with your
simulation setup successively increase the level of detail until enough geometric detail is
achieved. The benefit is precise control over memory usage and computation time.

Geometric structures resulting from DEM import are generic in the COMSOL environment and
handled in the same way as mechanical CAD. This means that the full power of COMSOL Multiphysics
is available for DEM geometry representations and can applied to any single physics or multiphysics
simulation such as subsurface flow, electromagnetics, acoustics, and structural mechanics.

Studies and Solvers

Parametric Sweeps: Accumulated Probe Tables and Response Surfaces

Parametric sweeps can now create Accumulated Probe Tables which enables a Probe to write
multiparameter data to tables. For example, the table can include the results from a nested
parametric sweep with two independent parameters. From the table you can create a new Table
Surface plot for plotting 2D response surfaces and a new Table Graph for a 1D graph plot of
the results versus a parameter.

A new user interface for memory conservative parametric sweeps makes it easier to run large
parametric sweeps where only a few derived scalar values, and not the entire solution, need to
be saved per parametric step.

Time-Dependent Mesh Adaption and Automatic Remeshing

The time-dependent mesh adaption and automatic remeshing capabilities have been enhanced
and generalized. The time-dependent mesh adaption algorithm now predicts the next mesh
refinement by pre-solving on a coarse mesh. For two-phase flow simulations this results in
an adaptive mesh that more closely follows the phase interface and gives more accurate results.

This example demonstrates how to model the fluid flow of an inkjet nozzle, for instance,
in a printer. An ink droplet is ejected through the nozzle and travels through air until
it hits the target. The fluid flow is modeled by the incompressible Navier-Stokes equations
with surface tension. This model uses the level set method and also makes use of adaptive meshing.

The new Table Surface feature makes it
easy to plot results as functions of multivariate
parametric sweeps. The pictures show the electric
field of a microstrip patch antenna together with
settings windows and a response surface plot of the S11 parameter vs. geometric width and frequency.

Combined Stationary and Time-Dependent Solutions

A new Study option gives you complete control over combined stationary and transient
simulations involving different physics phenomena. For each time-step of a transient
simulation you can automatically use a stationary solution of a different study and
physics. This has important applications for particle tracing, where the particle
trajectory simulation is transient but where particle forces are taken from a stationary
solution field. The new tools are available at the bottom of the Time Dependent Study
Step settings window in the section called Values of variables not solved for, and is
used in combination with the Physics Selection, which is available in the same settings
window.

Compare Solutions on Different Meshes by the Join Data Set

The new Join Data Set is used to compare solutions corresponding to different meshes,
time steps, or parameter values. You can form combinations of solutions using the operations
difference, sum, product, quotient, and more general and explicit expressions. An important
application for the Join Data Set is to plot and evaluate the difference between two solutions
in a mesh convergence study.

Multislice Plots

Multislice plots provide a shortcut for generating multiple slices in different directions.
The default option is to create three slice planes parallel to the x, y, and z coordinate planes.
The Multislice plot type is one of the quickest ways to probe the inside of the computed domain
and is available in the More Plots section of any 3D Plot Group.

Isosurface levels can now be interactively changed using a slide controller. Multiple isosurfaces can be simultaneously positioned.

Custom Plot Titles

The Title section for plots now provides a Custom setting for creating a customized
plot title. When you select Custom you get a number of options for the typical components
of a plot title: the data set, its phase and solution when applicable, and the type,
description, expression, and unit for the plotted quantity. You can also add a user-defined
prefix and suffix.

This visualization shows the
difference in temperature between
solutions corresponding to two
different mesh densities for a thermal stress simulation.
The new Join Data Set is used to compare solutions corresponding to different
meshes, time steps, or parameter values.

Interactive Slice and Isosurface Plots

Any scalar quantity of interest can be visualized by slice plots or isosurface plots.
Quantities visualized can be one of many predefined expressions or be typed in as a
user-defined expression. New in version 4.2a is that slice plots and isosurface plots
can be interactively positioned using a slide controller. Slices may be created by giving
the total number of evenly distributed slice planes or by exact positioning using coordinate
values. Similarly, isosurfaces may be created giving the total number of evenly distributed
isosurface levels or the exact value of the levels. Isosurfaces may in addition be colored
using a completely different field quantity as a Color Expression. A non-interactive slice
or isosurface plot can be turned into an interactive by just selecting a checkbox.

Data Operations on Results

Several new operators are available for postprocessing. For
time-dependent simulations the timeint() operator enables time
integration of already computed time-dependent solutions. The timeavg()
operator similarly computes the time-averaged value of any expression.

For small-signal and prestressed analysis, the operator lintotalavg()
evaluates the average of an expression over all phases for a linearized
solution. The operator lintotalrms() evaluates the root mean square
(RMS) of an expression over all phases for a linearized solution. The
operator lintotalpeak() evaluates the maximum of an expression over all
phases for a linearized solution.

Model Builder Tree Updates

You can now select multiple nodes of the Model Builder tree simultaneously to
quickly delete entire chunks of model definitions. New Previous Node and Next Node
arrow buttons helps quick navigation between modeling steps.

Automatic Inverse of Interpolation Data

The Interpolation table feature has been extended with an automatic function inverse.
This option is available in the Interpolation settings window for 1D interpolation tables.
If the original function has the name int1(x), then its inverse is by default made available
as int1_inv(x). The name of both functions can be edited. Interpolation table functions and
function inverses are made available in most text fields including those for initial conditions,
material settings, boundary conditions, and results.

Units and Material Properties in Equation-Based Models

The equation-based interfaces for Partial Differential Equations (PDEs),
Ordinary Differential Equations (ODEs) and Differential Algebraic Equations
(DAEs) now support units. By declaring quantities for the dependent variables
and the source terms, the equation interfaces define and display units for
all equation terms and quantities. This makes it possible to mix equation-based
modeling with other physics interfaces and at the same time make full use of
the unit system in the model. You can switch off the unit handling for working
with dimensionless quantities.

For equation-based modeling you can now access material property variables of
library materials when defining your own expressions or equations. A New material
container variable root.material simplifies access to material data. For example,
root.material.rho is the density rho as defined by the materials in each domain in
the geometry. For visualization, you can type the expression material.rho to create
a plot that shows the density of all materials.

Unit handling is now available for partial differential equation modeling. In this
example, the expression nitf.Cp*nitf.rho is automatically identified
as having the correct unit J/(m^3*K). Expressions with wrong units are highlighted in orange.

CFD Module

New k-ω Turbulence Model

The well-known k-ω turbulence model is now available in the CFD Module Version 4.2a.
and corresponds to the so called revised Wilcox model. Even though it can be more demanding
to apply than the standard k-ε model, it can often
give more accurate results. The turbulence modeling user interfaces of the CFD Module use
the Reynolds-averaged Navier-Stokes (RANS) equations and solve for the averaged velocity
field and averaged pressure. In addition to the new k-ω turbulence model, different
models for the turbulent viscosity are available since earlier versions: a standard
k-ε model, a Low Reynolds number k-ε model, and a Spalart-Allmaras model.

A simulation of water flow in a 90 degree
pipe elbow. The flow is simulated using the newly added k-omega
turbulence model. The result is compared to engineering correlations
and this tutorial is available on the web through COMSOL’s Model
Library Update.

Laminar Euler-Euler Two-Phase Flow

The new Euler-Euler Model user interface for two-phase flow is able to handle similar
types of simulations as the Bubbly Flow and Mixture Model user interface but is not limited
to low concentrations of the dispersed phase. In addition, the Euler-Euler Model interface
can handle large differences in density between the phases, such as the case of solid
particles in air. This makes the model suitable for simulations of fluidized beds.

Snapshots of the solid phase volume fraction inside a two-dimensional fluidized bed, taken at four different times; t = 10s, 13s, 16s, and 19s after the start of the simulation. Air is injected at the bottom of the bed, while the solid phase and air is injected through two vertical slots just above the air inlet. The solid inlet mass flux is kept at a rate matching the outlet flux at the top of the bed.

Interior Wall

The new Interior Wall boundary condition for single-phase flow makes it easy to define
a thin-wall condition between two fluid domains. You no longer need to define a solid domain
with a wall boundary condition on both sides, which can result in a dense mesh. This new
boundary condition is available in both the CFD Module and the Heat Transfer Module and can
also be used together with the Fluid-Structure Interaction multiphysics interface of the
Structural Mechanics Module and the MEMS Module.

External Radiation Sources

External radiation sources can now be defined in the Heat Transfer
Module as sources at infinity or as point sources at finite distance.
This option is available in the Heat Transfer physics interface and any
physics interface that supports surface-to-surface radiation. When defining
a source at infinity, the power per unit area is input. This is typically
used for incident sun radiation. When defining a point source at finite
distance, the total power input is given.

Another new important feature of the Heat Transfer Module is that it
you can define radiation on both sides of a boundary when surface-to-surface
radiation is used. This new option is available in the Heat Transfer physics
interface and any physics interface that supports surface-to-surface radiation.

New Structural Mechanics Features

Expanded Structural Shell Capabilities

The Structural Mechanics Module now supports offsets for shells. This shell
property makes is possible to model thin structures where the midsurface is offset
from the location of the boundary of the original COMSOL geometry. It also applies
to imported CAD models.

Prestressed modal and frequency-response analysis has been available for solids
since the previous release and is now also made available for shells. When used for
geometrically nonlinear analysis, a shell can be predeformed or prestressed and the
modified modal frequency is automatically computed with aid of a very sophisticated
and general linearization algorithm. Applications include vibration analysis of any
type of prestressed shell structure.

The new version of the Structural Mechanics Module has expanded shell modeling
functionality with surface offsets and prestressed vibration analysis. The picture
shows surface contours of the von Mises stress at the bottom evaluation level of
a bracket shell structure.

New Ways to Specify Isotropic, Orthotropic, and Anisotropic Materials

The Structural Mechanics Module, the Acoustics Module, and the MEMS Module have general
support for isotropic, orthotropic or generally anisotropic materials. Voigt material data
order is now supported in addition to the previously available standard material data order.
The Elastic Waves and Poroelastic Waves interfaces of the Acoustics Module now use Voigt
notation by default.

A total of nine different ways of specifying elastic data are now available. The latest
addition is that elastic data can be given by the combination of Young’s modulus (E) and shear
modulus (G).

New Tutorial Models

The new version of the Structural Mechanics Module includes five new tutorials for important applications:

Postbuckling Analysis of a Hinged Cylindrical Shell
Tracing of a postbuckling path where neither the load nor the
displacement increases monotonously.

Polynomial Hyperelastic Model
This model shows how to implement a Mooney-Rivlin constitutive
material model using a user-defined strain energy density.

Sheet Metal Forming
Demonstration of plastic metal forming using a rigid punch with
elastoplastic deformation, contact, and friction. The results
are compared with experimental data.

Nonlinear Magnetostrictive Transducer
The magnetic field and displacement as functions of the applied
current are computed for a magnetostrictive transducer where the
BH curve is nonlinear. This model considers the case when the
material is sufficiently prestressed so as to obtain the maximum
magnetostriction.

Vibration of an Impeller
A tutorial model that demonstrates the use of dynamic cyclic
symmetry with postprocessing on the full geometry. This Model
can be downloaded from the Model Library Update feature.

Acoustics Module

Fluid Models for Pressure Acoustics

The Pressure Acoustics interface of the Acoustics Module includes a number of new
fluid models. Losses can be accounted for in several different ways in the Acoustics
Module. The most advanced user interface covers full Thermoviscoacoustics phenomena.
Another way to introduce losses are by using so-called equivalent fluid models directly
in the Pressure Acoustics interfaces. This introduces attenuation properties to the bulk
fluid in contrast to the thermoacoustic model. The models include losses due to thermal
conduction and viscosity, models for simulating the damping in certain porous materials,
and macroscopic empirical models for certain fibrous materials. When applicable, the
equivalent fluid models are computationally much less heavy than, for example, solving
a corresponding full poroelastic model.

Additional Perfectly Matched Layers

Perfectly Matched Layers (PMLs) for absorbing outgoing acoustic and elastic waves are
now also available for Poroelastic Waves, Thermoacoustics, and Structural-Acoustic Interaction.
Since earlier versions, PMLs have been available for Elastic Waves, Piezoelectric Waves, Pressure
Acoustic Waves and Electromagnetic Waves. PMLs are artificial materials that very efficiently dampen
waves and are used to represent infinite computational domains. They give very little or no reflection
for a wide range of frequencies and angles of incidence and generalize the concept of non-reflective
boundary conditions.

Thermoacoustic-Solid Interaction

The new version of the Acoustics Module has new multiphysics interfaces for thermoacoustic-solid
couplings in the frequency domain for 2D, 2D axisymmetric, and 3D models. The Thermoacoustic-Solid
Interaction interfaces combine features from the Thermoacoustics and Solid Mechanics interfaces.

New Tutorial Models

The new version of the Acoustics Module includes two new tutorials
for important applications:

Axisymmetric Condenser Microphone with Electrical Lumping
This model is that of a simple axisymmetric condenser microphone. The model includes all
the relevant physics and determines the sensitivity of the specific microphone geometry
and material parameters. The model uses a lumped approximation for the electric small-signal
problem but solves a full finite-element model for the acoustic-mechanical system. The
quiescent (zero-point) problem is solved fully using electrostatics and a membrane model.
This model requires both the Acoustics Module and the AC/DC Module.

Acoustic Levitator
This model is that of a simplified 2D acoustic levitator geometry driven at a constant frequency.
Small elastic particles are released uniformly in the standing acoustic field and their path is
determined when influenced by the acoustic radiation force, viscous drag, and gravity. This model
requires both the Acoustics Module and the Particle Tracing Module.View Screenshot

A new tutorial of a condenser microphone shows how to setup a multiphysics model
combining electrical, mechanical, and thermoacoustics effects. It is used to very
accurately determine the sensitivity to changes in the microphone geometry and
material parameters. This model combines the Acoustics Module and the AC/DC Module.

AC/DC Module

Capacitance and Lumped Parameter Matrices

A new Global Matrix Evaluation tool computes and displays an entire
lumped parameter matrix in one single step. The resulting matrices are
displayed directly in a table and they are also available for parametric or
frequency sweeps. This functionality is available for all lumped parameters:
capacitance, inductance, impedance, and admittance.

Results node and table output from a capacitance matrix computation using the new
Global Matrix Evaluation feature. A four-port electrostatics simulation results
in a 4-by-4 capacitance matrix which is displayed in table form.

Automatic Differential Inductance Computation

Small-signal analysis, which was introduced in Version 4.2, is now available with automated
differential inductance computations. This feature is also available for other lumped parameters
such as capacitance and impedance.

Particle Tracing with the AC/DC Module

The AC/DC Module can be easily be combined with the new Particle Tracing Module for
computing charged particle trajectories in electromagnetic fields. Two new examples
are available:

Magnetic Lens
This model uses the new Charged Particle Tracing user interface to compute the
trajectories of electrons in a spatially varying magnetic field. This model
requires both the Particle Tracing Module and the AC/DC Module.

Quadrupole Mass Spectrometer
This model computes the trajectories of ions of various molecular weights in a
quadrupole. There are both AC and DC components of the electric field. This model
requires both the Particle Tracing Module and the AC/DC Module.

Charged particle trajectories in a magnetic lens using a combination of the AC/DC Module and the Particle Tracing Module.

RF Module

S-Parameter Matrices

A new Global Matrix Evaluation tool computes and displays the entire S-parameter matrix
in one single step. For a frequency or geometric sweep it computes and displays the entire
matrix in a table - which can used for a response graph or surface visualization using new
table graph and table surface features.

An S-parameter matrix frequency sweep for a branch line coupler. The device can
be used for a single antenna TX/RX system or I/Q signal splitter/combiner.

MEMS Module

Electromechanics Multiphysics Interface

A new Electromechanics multiphysics interface combines solid mechanics and electrostatics with
a moving mesh to model the deformation of electrostatically actuated structures. Applications
include biased resonator computations with modal and frequency-response analysis as well as pull-in
voltage computations.

Several new electromechanical tutorials are available: a suite of 2D and 3D models of a biased
resonator showing how to model a stationary analysis, the frequency response, the normal modes, the
pull-in voltage, and the transient response. The 3D versions of this suite of models are available
from the Model Library Update.

Thin-Film Damping

The thin-fiIm damping user interface has been greatly simplified. You can now
add thin-film damping to a boundary directly in the Solid Mechanics interface. In
a Fluid-Film Properties subnode you define the fluid properties, gas properties,
and rarefaction effects. In a Border subnode you define the border condition: a
pressure or a border flow. The Film-Damping Shell interface still exists for coupling
film-damping and solid mechanics in the same way as in earlier versions using a
multiphysics coupling.

Slip Flow Interface

A new Slip Flow interface is available for modeling thermal and isothermal flows within
the slip flow regime. The Slip Flow interface makes it possible to model the flow of the gas,
including a thin layer of gas adjacent to the walls (Knudsen layer), where the gas is
significantly rarefied. The Slip Flow interface is available in 2D and 3D.

A new Slip Flow Benchmark example model shows the flow between two sealed chambers connected
by a microchannel with conducting walls. This model uses the new Slip Flow interface.

Transitional Flow Interface

A new Transitional Flow interface makes it possible to model isothermal flow across the full
range of Knudsen numbers from the laminar flow limit to the molecular flow limit. The Transitional
Flow interface is available in 2D.

A new Knudsen’s Minimum example model, using the Transitional Flow interface, shows that the
flow rate of a rarefied gas between parallel plates exhibits a minimum (Knudsen’s minimum) at a
Knudsen number of about 1.

A new Slip Flow Benchmark example model shows the flow between two sealed
chambers connected by a microchannel with conducting walls. This model uses the new Slip Flow interface.

Plasma Module

Ion Energy Distribution Function and Angular Distribution Function

By combining the Particle Tracing Module and the Plasma Module, it is now possible to compute the
ion energy distribution function and the angular distribution function. The Ion Energy Distribution
Function is important in semiconductor fabrication and surface treatment because it can be manipulated
to give precise control over the aspect ratio of nanometer size structures.

Capacitively Coupled Plasmas (CCP)

You can now plot cycle-averaged quantities for capacitively coupled plasmas (CCP). A new CCP benchmark
model is available that reproduced benchmark results for a one-dimensional capacitively coupled plasma.
The model is driven by a constant current rather than a constant voltage. The ion current, power deposition,
electron density, ion density and ion flux are all compared to published data.

CHEMKIN® Import and Parameter Estimation

The new version of the Chemical Reaction Engineering Module features improved performance for CHEMKIN
import and improved parameter estimation. In addition, three new model tutorials are available:

Parameter Estimation for Nonideal Reactor Models
In this example two ideal CSTRs with interchange are used to model a real reactor with one
highly agitated region and another region with less agitation. Two parameters, relating the
volume and exchange rate of the two regions, are found by parameter.

Microchannel H-cell
This model treats a microchannel H-cell for separation through diffusion. The cell puts two
different laminar streams in contact for a controlled period of time. The contact surface is
well defined, and by controlling the flow rate it is possible to control the amounts of species
that are transported from one stream to the other through diffusion. This highly-requested model
was available in Version 3.5a and is now reintroduced in Version 4.2a.

Stefan Tube
This example shows 1D steady-state multicomponent gas diffusion. The diffusion of three gases in
a Stefan tube is modeled in 1D using the Maxwell-Stefan Diffusion interface. The steady-state mass
fraction profiles are calculated. This highly-requested model was available in Version 3.5a and is
now reintroduced in Version 4.2a.

A flow cell in a biosensor contains an array of micropillars. The curved side of the pillars are
coated with an active material that allows for the selective adsorption of analyte species in the
sample stream. The adsorbed species produce a signal that is dependent upon the local concentration
at the pillar surfaces. This example investigates the surface concentration distribution in the
cell while an analyte pulse is transported through it. It also studies the effect of a quenching
surface reaction where adsorbed species are converted into an inactive state. The model illustrates
how to use the Surface Reactions interface while coupling mass transport in a fluid stream with
chemical reactions that occur on a surface.

Batteries & Fuel Cells Module

Infinite Elements for Current Balance

New Infinite Elements allow the current balance of electrodes
and electrolyte to account for unbounded, or infinite, domains.
The Infinite Elements are artificial modeling domains added to
the outside of the main model and automatically scales the equations
to infinity. Using this technique makes it possible to shrink the
simulation domain and yet increase the accuracy of a simulation,
lowering the computational cost. In the Model Builder Tree, the
Infinite Element Domain node is added directly under Model Definitions

New Tutorials

In the new version of the Batteries & Fuel Cells Module, two new model tutorials are available:

Liquid-Cooled Li-Ion Battery Pack
This model simulates the temperature profile in a liquid-cooled battery pack. The fluid flow
and temperature model are in 3D whereas a lumped 1D model of the batteries is used to calculate
the heat source. The model requires the Batteries & Fuel Cells Module and the Heat Transfer Module.

Electrochemical Impedance Spectroscopy in a Fuel Cell
This model demonstrates how to perform an electrochemical AC impedance simulation of a fuel cell.
It applies a dedicated study type which automatically linearizes the nonlinear simulation and superimposes a given AC signal.

Electrode Power Boundary Conditions

The Batteries & Fuel Cells Module now features an Electrode Power input
boundary condition for its Lithium-Ion Battery user interface as well as for
several additional user interfaces. You can choose between Average power density or Total power.

Cooling of a lithium-ion battery pack for automotive applications. This model simulates
the temperature profile in a liquid-cooled battery pack. The fluid flow and temperature
model are in 3D whereas a lumped 1D model of the batteries is used to calculate the heat
source. This model tutorial is now available in the Model Library of the Batteries & Fuel Cells Module.

Electrodepostion Module

Infinite Elements for Electrodeposition

Electrodeposition simulations sometimes include large surrounding
domains with little geometric detail that influences the
electrodeposition process. Such domains can then be approximated as
being infinitely large to save computational requirements. New
Infinite Elements allow for finite-sized representation of such
domains and include the current balance of large parts of electrodes
and electrolytes. In the Model Builder Tree, the Infinite Element
Domain node is added directly under Model Definitions.

New Tutorial: Electrodeposition of a Microconnector Bump

A new tutorial shows electrodeposition of a microconnector bump.
The deposition process is mass-transport limited and the impact of
varied fluid velocities on the current density distribution on the
electrode is investigated. Microconnector bumps are used in various
types of electronic applications for interconnecting components, for
instance liquid crystal displays (LCDs) and driver chips. Detailed
step-by-step instructions are available on HTML and PDF format.

The location of the bumps on the electrode surface is controlled by
the use of a photoresist mask. Control of the current distribution in
terms of uniformity and shape is important for ensuring the shape and
resulting reliability of the interconnector bumps.